diff --git a/src/portab.h b/src/portab.h
index cad424b..7059852 100644
--- a/src/portab.h
+++ b/src/portab.h
@@ -26,12 +26,6 @@
 
 #include "config.h"
 
-#ifdef DMALLOC
-#include <dmalloc.h>
-#endif
-
-#define	YES		1
-#define	NO		0
 #define OK		0
 #define NG	      (-1)
 #define true            1
@@ -40,7 +34,7 @@
 #ifndef FALSE
 #define FALSE           0
 #undef  TRUE
-#define TRUE            (!FALSE)
+#define TRUE            1
 #endif
 
 #define min(x,y) ((x) < (y) ? (x) : (y))
@@ -53,7 +47,7 @@ typedef	unsigned long  ___DWORD;
 #else
 typedef	unsigned int   ___DWORD;
 #endif
-typedef char           ___boolean;
+typedef _Bool          ___boolean;
 
 #ifndef BYTE
 #define BYTE ___BYTE